.box2 {
  width: 200px;
  height: 200px;
  background-color: blue;
}
.box2 p {
  font-size: 18px;
  color: aqua;
}
.box2 > a {
  text-decoration: none;
  font-size: 24px;
  color: red;
}
.box2::after {
  content: "黑马";
}
.box2_p {
  color: saddlebrown;
}
.box p {
  font-size: 18px;
  color: aqua;
}
.box > a {
  text-decoration: none;
  font-size: 24px;
  color: red;
}
.box::after {
  content: "黑马";
}
.box_p {
  color: saddlebrown;
}
